Looking at proactively replacing my 20+ yr old AC units (one upstairs / one downstairs) and I have a quote for each of the above. Quote also included single stage but that's not on the table.

I'm trying to decide if the added expense of 5 stage vs 2 is worth it. Likely won't go fully variable due to the fact those are super expensive (but seem awesome just not getting that $$$ past the rib).

Anyone have insight or experience in this decision making? Current quote is for Carrier machines and we're in Austin where this week it's hot as Hades already!

I've never even heard of a 5 stage unit. Why not properly sized single stage plus whole home dehumidifier? I have a 2 stage and would go that route (single/dehu) if I had to make the choice again.

I've never heard of a 5 stage but that doesn't mean much.

When the system needed to be replaced at our last house we upgraded from a single to a 2 stage. It was worth every penny as it totally changed the comfort level in our house. And when the system was running on the lower stage it was extremely quiet. We choose American Standard and selected the vendor based on interviews that focused on the quality of the install.

Also never heard of 5 stage. But we have variable and worth every penny, imo. We're in a pretty energy efficient townhome, so don't necessarily see as large of electricity savings, but crazy how much more comfortable the house is. Especially at night where it can just run at 30-40% steady and maintaining temp vs shutting off, warming up, turning back on at 100% or 70% (2 stage), and repeating.

The variable obviously helps with dehumidification, but more than just that.

I'd imagine 5 stage is similar.

5 stage was new to me too.

https://www.carrier.com/residential/en/us/products/air-conditioners/24vna9/

Sizing is 2.5 tons for up and 4.0 down. This 5 stage and the full variable differ by about $4k in total in this guy's quote.

I have a fully variable AC. I imagine a 5 stage has got to be pretty dang close to that.

I have asked repeatedly from my local Lennox and Carrier distributor what exactly their variable speed units run at range wise and have never gotten a concrete answer. Trane and Daikin run from 30%.31, 32 , 33 etc all the way up to 100 percent capacity. Lennox and Carrier won't tell me exactly but for reference 40, 50 , 60, 70, or 25, 50, 75, 100 type of increments.

So I guess it depends on how YOU define variable. 5 stage is going to along the same concept lines as 2 stage but it starts out at lower than 70 percent like all 2 stage units and then makes jumps up. The Trane and Daikin are just more dialed in to operate at more exacting settings if that makes sense.

So…different Lennox units run between different percentages. Mine goes from 40% to 100% in 1% increments. The reason I know that is because I read the entire manual myself. Actually, I created a fake dealer account so I could access Lennox Pro's website and literature. After I read all the literature, I had to get the installers back out there because their installation process reduced my variable unit to just a 2-stage unit. Their excuse was they were trying to save me a couple bucks on installation. What a load of garbage.

I imagine the installers don't know because they are just there to hook everything up and get paid. You know how it is. No one is going to care for your stuff like you do.

Job One is to work with a 5-star, BBB "A+" installer after you read ALL the reviews everywhere.
As you read above, this 2nd half quarterback can blow the game even with top-o-line equipment.

Job Two would be to respect who has been chosen as best brands by those in the know.

Job Three:
The 2-stage has been around for a looong time, so most anyone can install it, so long as ductwork is tight.
Some HVAC company owners still use this personally at home.
1st costs are seductive but power use & comfort suffer unless all rooms it serves are twins (all needing the same conditioning).

The 5-stage is new to me but seems similar to Variable.
If your life term with it is short and budget high priority, then this is IT.

The Variable is for long term or forever housing to justify the highest 1st cost
but it pays back every month in lower power bills and no matter the room demands,
everyone is most comfortable under its care. This statement almost includes Sunrooms, but not quite.

I will never ever again go less than Variable, now 2-years old pampered.

Those with a budget might figure things this way
Where does the most comfort need to be? Up or down stairs, active vs sleeping/docile?
Where does the most power get burned up?
What area can live OK with fewer stages?

In our case, I might choose Variable for sleeping zones and 2 to 5 stages for active zones.

TIP: in Active zones, inviting party guests is an extra cooling load in Texas summers.
20 guests require another 1 ton of AC, so this begs for more stages in a system if not oversized solely for parties.

I'd love to spend the big bucks on the fully variable but the wife is pushing back hard (our quote is pretty insane, a 2.5 ton & a 4.0 ton plus new furnaces for $35k) although I don't know if its out of line or not. I'm lining up more quotes to get a better feel for this price. Its a lot but not sure if its truly higher than anyone else or other equipment.

This compared to 2 stage at $27k and 5 stage at $31k.

Man...never thought I'd be happy with our AC going out in summer of 2020 even though I was unemployed at the time....

Are you referring to quote now versus a few years ago?

This AC guy prefaced the quote by telling me that equipment keeps getting more and more expensive. More and more efficient yes but at a larger upfront cost.

Yeah. We did a 4 ton, 20.3 SEER, variable unit Trane for $14.5k, gas furnace included as well.

Yeah this quote for the 4.0 with gas furnace fully var. is now $19k. The 2.5 he wants $16k.

Gotcha, didn't see the 2.5 as well!

My crazy shock is gone lol

Still up a bunch since 2020 for similar equipment. Damn inflation!